The present disclosure relates generally to displays and, more particularly, to displays generating scenes with electromagnetic radiation in a range of infrared wavelengths. In general, the scenes may be displayed at any selected wavelength, but for teaching purposes the scenes may be discussed as being displayed in a range of infrared wavelengths, which can be useful for certain applications.
Infrared imagining sensors form an image of received light from energy received in a range of infrared wavelengths, as do imaging sensors at other wavelengths. This image may be translated to the visible light spectrum for observation by a human observer, or the invisible wavelengths may be processed directly and actions taken based on this processing without human intervention or human viewing of the image. Calibration and testing of such imaging sensors is advantageously performed using synthesized imagery or scenes in real time in the waveband of the sensor. Typically, these images or scenes dynamically depict movement, thus requiring rapid imaging of many consecutive still scenes to depict the movement. In general, increasing the rate of acquisition of test imagery by the imaging sensor will increase the precision, stability, accuracy, and speed with which the sensor may be tested or calibrated. For example, at infrared wavelengths, an infrared scene synthesizer or display may accordingly be required to display scenes or images in a range of infrared wavelengths at a refresh rate that is compatible with the image acquisition rate of the infrared imaging sensor.
Generating infrared scenes depicting movement using conventional techniques has proven to be challenging. A typical manner of providing such scenes involves heating and cooling resistive elements in an array to provide infrared irradiance. Unfortunately, the thermal inertia of these elements limits the rate at which the scene can be refreshed and often results in artifacts in the scene. Further, resistive elements with pixel counts sufficient to match pixel counts of modern imaging devices are difficult and expensive to fabricate, and require large amounts of power. In addition, the resistive elements typically do not produce true blackbody spectra. The limited refresh rate, spectral inaccuracy, and artifact introduction can consequently interfere with calibration and testing. Hence, improvements in devices for displaying infrared dynamic scenes would be well appreciated in the infrared imaging sensor industry.